Generalized Supersymmetric Perturbation Theory

Using the basic ingredient of supersymmetry, a simple alternative approach is developed to perturbation theory in one-dimensional non-relativistic quantum mechanics. The formulae for the energy shifts and wavefunctions do not involve tedious calculations which appear in the available perturbation theories. The model applicable in the same form to both the ground state and excited bound states, unlike the recently introduced supersymmetric perturbation technique which, together with other approaches based on logarithmic perturbation theory, are involved within the more general framework of the present formalism.     

载能团簇离子诱发的非线性二次离子发射

载能团簇离子进入固体时, 由于集体相互作用,在入射路径上产生非常高的能量沉积密度。 实验发现, 载能团簇离子的作用结果并不等于团簇中各原子独立作用的总和, 而是具有非线性效应。 就二次离子发射而言, 这种非线性通常与团簇的能量、 团簇的大小、 离子的电荷态以及靶物质的结构有关。 通过研究二次离子发射有助于理解载能团簇离子与物质相互作用过程中的能量沉积与释放机制。 Using energetic cluster as projectile is a unique way to produce simultaneous impacts of several atoms and deposit extremely high energy density in a very small area. The cluster impingement on solids has exhibited some non linear effects not presented in collisions of individual atoms with those solids. The study of the secondary ion emissions can give insight into the energy deposition and relaxation steps of the cluster solid interaction. The dependence of the yields of secondary ion emission induced by clusters on the energy of clusters,cluster sizes,charge states and material structures of the targets was reviewed in this paper.     

High-Order Hamilton＇s Principle and the Hamilton＇s Principle of High-Order Lagrangian Function

In this paper, based on the theorem of the high-order velocity energy, integration and variation principle, the high-order Hamilton＇s principle of general holonomic systems is given. Then, three-order Lagrangian equations and four-order Lagrangian equations are obtained from the high-order Hamilton＇s principle. Finally, the Hamilton＇s principle of high-order Lagrangian function is given.     

A Helium Atom Confined by a Spherical Gaussian Potential Well

The helium atom confined by a non-impenetrable spherical box, i.e., a spherical Gaussian potential well which possesses finite height and range, is studied employing the exact diagonalization method. Total energies of the ground and three low-excited states are obtained as a function of the confined potential radii. We find that the confinement may cause accidental degeneracies between levels with different low-excited states and the inversion of the energy values. The results for the three-dimensional spherical potential well and the two-dimensional disc-like potential well are compared with each other： in general, the energies of the states decrease and the energy intervals between states increase with the reduction of the space dimensions.     

射频超导技术与ERL技术新进展

射频超导谐振腔可以工作在连续波或长宏脉冲模式.射频超导技术已发展为加速各种带电粒子束的重要手段.射频超导技术发展的前期受材料性能、腔的处理以及加工安装水平等的限制.经过几十年的不断改进,射频超导技术获得了重大突破.射频超导腔应用到超导加速器上并成功运行,积累了腔的质量控制工艺和工业化制备的大量经验.近期国际上面对未来大科学装置项目,在射频超导技术方面进行了大量的研发工作,主要包括提高超导腔加速梯度的新腔型研究和采用新型材料(大晶粒铌材)超导腔的研究.能量回收直线加速器(ERL)技术是近年来获得发展的重要加速器技术.ERL具有高效、节能、稳定性好、低辐射水平等优势,被越来越多地应用到先进光源和自由电子激光装置中.     

Micromegas prototypes with thermo-bond film separators

In this paper we report the results of Micromegas prototypes constructed by attaching micromesh to an anode using thermo-bond films. The excellent metal attaching ability and good dielectical property of this kind of film make it a promising material to be used as avalanche gap spacers. Several prototypes are successfully made. The electron transmission properties are first studied and then the gas gain is measured in argon-isobutane mixtures. The maximum gain of more than 10⁴ is easily obtained. The energy resolutions for ⁵⁵Fe 5.9 keV K_α ray can be better than 20% over one magnitude in gain for different operational gas mixtures and the best energy resolution of 13.7% (FWHM) can be achieved with the gas mixture of 94% argon concentration. The preliminary test results of the prototypes with sensitive area of 45 mm×45 mm without internal support show good uniformity across the sensitive area.     

快离子导体AgxTiS2中Ag+离子-空位的二维基态结构与能量性质研究

根据Ag 离子-空位的二维有序结构建立了三维晶胞模型.采用局域密度近似下的平面波赝势方法,对有序Agx Tis2(x=0,1/4,1/3,1/2,2/3,3/4,1)系列进行了几何结构优化和总能量计算,并与Lix Tis2系列进行了对比研究.有序Agx Tis2系统的晶格参量增量△a0 和△c0随离子浓度单调增加,与实验结果符合得较好.有序Agx TiS2和Lix Tis2系统的总能量均随插层离子浓度增加线性下降,且前者下降较快.有序Agx TiS2(x=0,1/4,1/3,1/2,2/3,3/4,1)系统的形成能均小于零,表明其基态性质.具有3a0x3a0超结构的Ag1/3 Tis2系统的形成能最低.能量性质的对比显示,有序Agx TiS2系统的形成能较低,有序一无序相变温度较高,离子扩散活化能较高.根据计算结果对有关实验给出了合理解释.     

基于小波变换的堆积啁啾光脉冲时频分析

以复Morlet函数作为小波母函数推导了2M路线性啁啾高斯脉冲堆积形成的整形脉冲的时间分辨能量谱密度解析表达式。通过小波变换获得了堆积啁啾脉冲功率和瞬时波长随时间的分布; 堆积啁啾高斯脉冲功率随时间呈现振荡变化, 瞬时波长在功率接近零的极小值点发生跳变; 啁啾的增大会加剧功率的时域振荡和瞬时波长的跳变; 瞬时波长的跳变仅发生在功率接近零的极小值附近, 脉冲的能量仍然主要集中在由基元脉冲啁啾决定的波长范围内。同时, 研究表明脉冲重叠因子的微小变化会极大地影响整形脉冲峰值功率与等效平均功率之比和包络平坦度, 且两者不能同时达到最佳, 需折衷选取。